1. Field of the Invention
The present invention relates to a dry sump lubricating device for an internal combustion engine.
2. Description of Background Art
An internal combustion engine having a dry sump lubricating device includes an oil tank for storing oil pumped by a scavenge pump. The oil tank is generally configured by being defined in a crankcase, or is configured between a crankcase and a crankcase cover, if the crankcase cover is provided. See, for example, JP-A No. 2004-108257.
The lubricating device disclosed in JP-A No. 2004-108257 is configured in such a manner that the oil pumped by the scavenge pump of a trochoid type is supplied to the oil tank from a supply port for the tank located nearest to a front case cover (crankcase cover) through an oil cooler. The oil stored in the oil tank is sucked from a suction port which is open at a lower portion of the oil tank by a feed pump of a trochoid type. In addition, the oil discharged from a discharge port of the feed pump is supplied to respective regions for lubrication of the internal combustion engine.
In the dry sump lubricating device, when the oil is supplied to the oil tank from the supply port for the tank by the scavenge pump, bubbles are mixed in the oil. Further, bubbles are also mixed in the oil sucked by the feed pump. Thus, there is a high possibility that the feed pump causes cavitation.
A hydraulic pressure of the oil to be supplied to the respective regions for lubrication is not stabilized due to the cavitation of the feed pump.